add basic len check to Decode

README.md

@@ -64,11 +64,14 @@ if err != nil {
 fmt.Println(uuid) // Output: d1756360-5da0-40df-9926-a76abff5601d
 ```
 
-4. Decode a Key to a UUID string without validation:
+4. Decode a Key to a UUID string with basic length validation:
 
 ```go
 key, _ := uuidkey.Parse("38QARV0-1ET0G6Z-2CJD9VA-2ZZAR0X")
-uuid := key.Decode()
+uuid, err := key.UUID()
+if err != nil {
+    log.Fatal("Error:", err)
+}
 fmt.Println(uuid) // Output: d1756360-5da0-40df-9926-a76abff5601d
 ```
 
@@ -91,7 +94,7 @@ Package uuidkey encodes UUIDs to a readable Key format via the Base32\-Crockford
 - [type Key](<#Key>)
   - [func Encode\(uuid string\) \(Key, error\)](<#Encode>)
   - [func Parse\(key string\) \(Key, error\)](<#Parse>)
-  - [func \(k Key\) Decode\(\) string](<#Key.Decode>)
+  - [func \(k Key\) Decode\(\) \(string, error\)](<#Key.Decode>)
   - [func \(k Key\) String\(\) string](<#Key.String>)
   - [func \(k Key\) UUID\(\) \(string, error\)](<#Key.UUID>)
   - [func \(k Key\) Valid\(\) bool](<#Key.Valid>)
@@ -104,7 +107,7 @@ Package uuidkey encodes UUIDs to a readable Key format via the Base32\-Crockford
 ```go
 const (
     // KeyLength is the total length of a valid UUID Key, including hyphens.
-    KeyLength = 31
+    KeyLength = 31 // 7 + 1 + 7 + 1 + 7 + 1 + 7 = 31 characters
 
     // KeyPartLength is the length of each part in a UUID Key.
     // A UUID Key consists of 4 parts separated by hyphens.
@@ -159,10 +162,10 @@ Parse converts a Key formatted string into a Key type.
 ### func \(Key\) [Decode](<https://github.com/agentstation/uuidkey/blob/master/codec.go#L62>)
 
 ```go
-func (k Key) Decode() string
+func (k Key) Decode() (string, error)
 ```
 
-Decode will decode a given Key into a UUID string without validation.
+Decode will decode a given Key into a UUID string with basic length validation.
 
 <a name="Key.String"></a>
 ### func \(Key\) [String](<https://github.com/agentstation/uuidkey/blob/master/uuidkey.go#L28>)

codec.go

@@ -31,7 +31,7 @@ func decode(s string) string {
 
 // Encode will encode a given UUID string into a Key with basic length validation.
 func Encode(uuid string) (Key, error) {
-	if len(uuid) != UUIDLength {
+	if len(uuid) != UUIDLength { // basic length validation to ensure we can encode
 		return "", fmt.Errorf("invalid UUID length: expected %d characters, got %d", UUIDLength, len(uuid))
 	}
 
@@ -58,8 +58,12 @@ func Encode(uuid string) (Key, error) {
 	return Key(e1 + "-" + e2 + "-" + e3 + "-" + e4), nil
 }
 
-// Decode will decode a given Key into a UUID string without validation.
-func (k Key) Decode() string {
+// Decode will decode a given Key into a UUID string with basic length validation.
+func (k Key) Decode() (string, error) {
+	if len(k) != KeyLength { // basic length validation to ensure we can decode
+		return "", fmt.Errorf("invalid Key length: expected %d characters, got %d", KeyLength, len(k))
+	}
+
 	// select the 4 parts of the key string
 	key := string(k) // convert the type from a Key to string
 	s1 := key[0:7]   // [38QARV0]-1ET0G6Z-2CJD9VA-2ZZAR0X
@@ -80,5 +84,5 @@ func (k Key) Decode() string {
 	n3b := n3[4:8]
 
 	// build and return UUID string
-	return (n1 + "-" + n2a + "-" + n2b + "-" + n3a + "-" + n3b + n4)
+	return (n1 + "-" + n2a + "-" + n2b + "-" + n3a + "-" + n3b + n4), nil
 }

uuid_benchmark_test.go

@@ -37,23 +37,23 @@ func BenchmarkEncode(b *testing.B) {
 	uuid := "d1756360-5da0-40df-9926-a76abff5601d"
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		uuidkey.Encode(uuid)
+		_, _ = uuidkey.Encode(uuid)
 	}
 }
 
 func BenchmarkDecode(b *testing.B) {
 	key := uuidkey.Key("38QARV0-1ET0G6Z-2CJD9VA-2ZZAR0X")
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		key.Decode()
+		_, _ = key.Decode()
 	}
 }
 
 func BenchmarkValidateInvalid(b *testing.B) {
 	key := uuidkey.Key("38QARV0-1ET0G6Z-2CJD9VA-2ZZAR0") // Invalid key
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		key.Valid()
+		_ = key.Valid()
 	}
 }
 

uuidkey.go

@@ -8,7 +8,7 @@ import (
 // Key validation constraint constants
 const (
 	// KeyLength is the total length of a valid UUID Key, including hyphens.
-	KeyLength = 31
+	KeyLength = 31 // 7 + 1 + 7 + 1 + 7 + 1 + 7 = 31 characters
 
 	// KeyPartLength is the length of each part in a UUID Key.
 	// A UUID Key consists of 4 parts separated by hyphens.
@@ -87,5 +87,5 @@ func (k Key) UUID() (string, error) {
 	if !k.Valid() {
 		return "", errors.New("invalid UUID key")
 	}
-	return k.Decode(), nil
+	return k.Decode()
 }

uuidkey_test.go

@@ -62,7 +62,10 @@ func TestEncodeDecode(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Encode() returned an unexpected error: %v", err)
 	}
-	decodedUUID := key.Decode()
+	decodedUUID, err := key.Decode()
+	if err != nil {
+		t.Fatalf("Decode() returned an unexpected error: %v", err)
+	}
 
 	if decodedUUID != uuidStr {
 		t.Errorf("Encode/Decode roundtrip failed. Got %s, want %s", decodedUUID, uuidStr)